Interrupts are commonly used today in data processing systems, especially in many real-time control applications. For example, a data processing system which is controlling an automobile engine may receive an interrupt request from the anti-lock braking system when the anti-lock braking system detects that the automobile has entered a skid. The maximum amount of time it will take the data processing system to respond to the interrupt is called the "maximum interrupt latency time". In most data processing systems, it is desirable to have the shortest possible interrupt latency time without reducing the normal operating performance of the data processing system.
In many real-time control applications, the maximum interrupt latency time is very important, and may even determine which data processing system is chosen for a particular application. In the example above, if a data processing system cannot respond fast enough to the interrupt from the anti-lock braking system, another data processing system with a shorter interrupt latency time will be chosen and used. It is thus very important in the data processing art to reduce the maximum interrupt latency time without significantly reducing the normal operating performance of the data processing system